Sydney, Jul 8 (IANS): Researchers are developing a laser system for a non-invasive, on-site breath analysis that can screen various diseases including diabetes, infections and cancer in a moment.

The team from University of Adelaide has developed an instrument like an "optical dog's nose" that uses a special laser to measure the molecular content of a sample of gas, which can hit the market in three-five years.

"The laser system uses light to 'sense' the range of molecules that are present in the sample," said James Anstie, research fellow with the university's Institute for Photonics and Advanced Sensing (IPAS).

Those molecules are by-products of metabolic processes in the body and their levels change when things go wrong.

Diseases like lung and oesophageal cancer, asthma and diabetes can be detected in this way even before external symptoms are showing, said the study that appeared in the journal Optics Express.

The system uses a specialised laser that sends up to a million different light frequencies through the sample.

Each molecule absorbs light at different optical frequencies and, therefore, has a unique molecular fingerprint.

"The next step is to work out how to accurately sample and interpret the levels which will naturally vary from person to person," the researchers said.

Other potential applications include measuring trace gasses, such as atmospheric carbon dioxide, and detecting impurities in natural gas streams.